For some interesting behavioral as well as neurophysiological evidence
pertaining to auditory visual interactions, see the following:
Stein, B.E., Wallace, M.T. and Meredith, M.A. (1995) Neural mechanisms
mediating attention and orientation to multisensory cues. In The Cognitive
Neurosciences, M. Gazzaniga Ed., MIT press, Cambridge, Mass., pp. 683-702.
Knudsen, E.I. and Brainard, M.S. (1995) Creating a unified represenation of
visual and auditory space in the brain. Annual Review of Neuroscience, 18,
19-43.
These studies have shown that under at least some conditions, stimuli that are
subthreshold in one or the other modality alone can be responded to when
they're combined, hence demonstrating some nonlinear interactions. Stein and
colleagues have provided neurophysiological evidence that neurons within the
deep layers of the feline superior colliculus contain topographic maps of both
visual and auditory space, and that large enhancements of response are
observed to combined auditory and visual stimulation; this structure may
therefore be one substrate for integration of the two modalities. In addition,
it has been shown that inputs from unimodal neurons within polysensory
cortical areas are important determinants of SC integration of response.
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Robert J. Zatorre, Ph.D.
Montreal Neurological Institute
3801 University St.
Montreal, QC Canada H3A 2B4
phone: 1-514-398-8903
fax: 1-514-398-1338
e-mail: md37@musica.mcgill.ca